8.6 AEROBIC FITNESS LEVEL AND PERIPHERAL ARTERIAL COMPLIANCE – THE ROLE OF AUTONOMIC NERVOUS SYSTEM TONE

Abstract

Physical activity has beneficial effects on prevention of cardiovascular disease. Aerobic fitness is associated with higher central arterial compliance, but its effect on peripheral arterial compliance (pC) is controversial. We aimed to test the hypotheses that aerobic training augments pC at rest and during different autonomic nervous system provocations (ANSP) inyoung healthy men. We enrolled 44 males, 19–24 years old (22 trained, VO2max=485ml/kg/min – group A, 22 sedentary controls, VO2max=303ml/kg/min – group B). VO2max was determined using cycloergometry (QuarkCPET, Cosmed). On the testing day, ECG, arterial blood pressure (Finapres, Ohmeda) and finger artery compliance at rest, 3 minutes during 0.1Hz breathing and 3 min during mental stress were measured. A noninvasive method was used to determine compliance index (CI), calculated as an average of the pressure dependant compliance curve in the range of arterial pressures from 97 to 105mmHg. Our results revealed elevated CI in group A compared to group B (4.18±0.38 and 1.28±0.25, p=0.004) at rest and no significant differences in CI between groups during ANSP (1.34±0.20 at 0.1Hz breathing and 0.82±0.18 during mental stress in group A compared to 1.09±0.21, p=0.06, and 0.60±0.12, p=0.08 in group B). A statistically significant positive linear correlation existed between CI and VO2max (P<0.001) at rest in group A, however, no correlation was found at both ANSP. Regular aerobic training increases pC in healthy young subjects at rest, but not during 0.1Hz breathing or mental stress. Our findings indicate that peripheral and not central autonomic mechanisms govern pC in young healthy males.